Im taking him out to London, UK where we live
If anyone lives in London and knows any awesome places a 19yr old guy would want to go please let me know
And please don't say the usual (london eye, parliament, etc etc been there done all that)
And also what else I can do to make his birthday unfortgetful
We have been tgether nearly 4 yrs so it has to be special
I have a budget of £80-100
Please help.

Decorate his room with flowers and good curtains so that as he wakes up on that day he finds himself very special. Wish him on his birthday with beautiful birthday cards (http://www.123greetings.com/birthday/). Serve him breakfast cooked by you. Gift him his favorite sports magazine or electronic gadgets according to his passion. Take him out for the whole day. Go to those places where you have spent your best days and cherish those moments. Then go for a lovely candle lit dinner for two. Don't you think the evening is already special.

I really like the answer above!

What are some things that have a special interest for him, please? I hope that he hasn't had his birthday yet..